Evaluation of the Vaginal Panel Realtime PCR kit (Vircell, SL) for diagnosing vaginitis: A comparative study with routinely used diagnostics

Abstract

Vaginitis is a prevalent clinical disorder associated with several adverse health consequences, prompting women to seek medical care. In this study we evaluate the Vaginal Panel Real-Time PCR kit (qPCR test) against routinely used diagnostics for detection of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), and trichomoniasis. A total of 1011 vaginal swab specimens were analyzed. The routinely diagnostic methods for BV was Gram stain-based Nugent score. VVC presence was detected by culture, and Candida species were identified using MALDI-TOF MS. Trichomonas vaginalis was identified by culture in a selective medium. Molecular analyses were conducted on the MagXtract® 3200 System and analyzed using the CFX96™ Real-Time PCR Detection System. The sensitivity, specificity, positive predictive value, and negative predictive value of the qPCR test compared to the reference method for BV diagnosis was 93.1%, 88.8%, 90.1% and 92.2%, respectively, with a Kappa value of 0.82. For Candida species, sensitivity, specificity, positive predictive value, and negative predictive value were 96.0%, 98.4%, 95.3%, and 98.7%, respectively. The qPCR test detected 32 additional positive samples for Candida not reported by the routinely used diagnostics. For trichomoniasis, the qPCR test identified T. vaginalis in fifteen specimens, despite no microscopic detection in cultured specimens. Our results demonstrate that the Vaginal Panel Real-Time PCR kit shows optimal concordance with routinely used diagnostics for diagnosing vaginitis. Furthermore, enhancing detection of T. vaginalis. However, further validation studies are necessary to confirm its full diagnostic accuracy. The use of nucleic acid amplification tests (NAATs) provides rapid and accurate diagnosis, crucial for early detection and treatment of vaginitis.

Fig 1. Flowchart illustrates a summary of the experimental methodologies and analytical procedures employed in the study.

BV, bacterial vaginosis; VVC, vulvovaginal candidiasis; MALDI-TOF MS, matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Fig 2

Scatter dot plots show the bacterial load (log copies/mL) of Lactobacillus spp., G. vaginalis and F. vaginae for the four categories of the Vaginal Panel Realtime PCR Kit (A) and the three categories of Nugent score (B). The mean and standard deviation (SD) are represented for each microorganism (C). Comparing the profiles of both methods, the qPCR test shows a greater variation in the bacterial load of the three microorganisms between BV G4 and NM G1 (A). In contrast, Nugent score shows a steadier profile across the different scores (B). G1-G4, grade 1, 2, 3 and 4; BV, bacterial vaginosis; NM, normal microbiota.

Fig 3. Percentage rate of samples with single and multiple infection reported by routinely used diagnostics and the Vaginal panel realtime PCR Kit.

BV, bacterial vaginosis; VVC, vulvovaginal candidiasis.